Sep 24, 2011

The sneaky science of “cloaking” just keeps getting richer. Physicists and engineers had already demonstrated rudimentary invisibility cloaks that can hide objects from light, sound, and water waves. Now, they’ve devised an “antimagnet” cloak that can shield an object from a constant magnetic field without disturbing that field. If realized, such a cloak could have medical applications, researchers say.

“This will take cloaking technology another step forward,” says John Pendry, a theorist at Imperial College London and co-inventor of the original cloaking idea, who was not involved in the present work.

In fact, shutting out a static magnetic field to protect an object isn’t that hard. All a researcher needs to do is to encase the object in a container made of a “superconductor,” a material that will carry electrical current without any resistance when it is cooled sufficiently close to absolute zero. If the container encounters a magnetic field, currents within the conductor will flow to generate a field that counteracts the applied field. In an ordinary conductor, the resistance of the metal quickly snuffs out those currents. In a superconductor, however, those currents just keep flowing, creating a magnetic field that exactly cancels the applied field and zeroing out the total field within the container.

But that doesn’t make a superconducting can a magnetic cloak. That’s because outside the can, the field produced by the superconductor will alter the applied field and reveal its presence. In a nutshell, the field can be thought of as a distribution of lines of force that vaguely resembles a weather map of winds. The superconducting shield pushes the magnetic field lines outward, creating a hole in the field. So the trick to making a cloak for static magnetic fields is to counteract that distortion. In 2007, Pendry and Ben Wood, also of Imperial College London, proposed that such a cloak could be made of a material that repels magnetic fields in one direction and attracts them in the opposite direction. Unfortunately, this self-contradicting material doesn’t exist.

But Alvaro Sanchez of the Autonomous University of Barcelona in Spain and colleagues propose a way to approximate the impossible stuff by wrapping the cylindrical shell of superconductor in layers of materials that do one job at a time. Some layers are easily magnetized and will essentially pull the external magnetic field lines around the cylinder; those layers alternate with shells of superconducting plates that push on the field, preventing it from coming straight in toward the center. The attracting layer would be made of tiny magnetic particles, like submicroscopic iron filings, mixed into a nonmagnetic material such as plastic.

The cloak could handle fields of any shape and any strength within what the superconductor can stand. If the external field gets too strong, the magnetically induced current becomes so powerful that it knocks the superconductor out of its resistance-free state and ruins its field-repelling qualities. Computer simulations showed that the cloak could work with as little as four layers, but with 10, it would guide a magnetic field nearly as well as a perfect cloak, as Sanchez and colleagues report today in the New Journal of Physics. “It doesn’t need to be a closed cylinder; it can be an open cylinder or open plate, although in this case the magnetic cloaking properties are reduced,” Sanchez says.

The hypothetical device would work as a magnetic cloak by creating a space that is protected from an external magnetic field while at the same time causing no telltale distortion of the field. Alternatively, it could also be used to conceal a magnetic object and prevent its magnetic field from extending out into space—a pie-in-the-sky dream for shoplifters trying to steal clothes pinned with magnetic security tags.

Mary Anning (1799–1847) is known in many circles as the greatest fossil hunter of all time, and this year marks 200 years since her most famous discovery: the first complete skeleton of a dinosaur-era sea monster known as an ichthyosaur. Anning found the 200-million-year-old, fish-shaped beast, and many others, eroding out of spectacular seaside cliffs near her hometown of Lyme Regis, along England’s Jurassic Coast.

To commemorate the anniversary, and Anning’s lifetime of discovery, Anning’s ichthyosaur has come back home. On loan from Natural History Museum in London, the bones are now on display at the Lyme Regis Museum, where several Mary Anning Day events are happening this weekend. In Cambridge, the Sedgwick Museum of Earth Sciences is celebrating as well, with a new display of the paleontologist’s personal letters and collected specimens.

To best appreciate Anning’s contributions to science, consider some history. In 1811 not much was going on to challenge the Biblical stories of creation and the flood. Certainly no one was thinking about evolution; Charles Darwin was still in diapers. James Hutton, the father of modern geology, had already theorized on the abyss of geologic time, but the idea would not become popular for another 20 years. No one yet appreciated the ancient world of extinct creatures that Anning’s discoveries would represent; indeed, it would be another three decades before Sir Richard Owen would coin the word “dinosaur.”

Yet starting at age 12, Mary Anning stretched the minds of her contemporaries like never before. In 1811, after months of painstaking effort, she had finally unearthed the entire skeleton of a strange animal she and her brother had spotted in the crumbling cliffs near their home. The unknown creature, now known as an ichthyosaur, had the sharp teeth of a crocodile, but its huge, bulbous eye made it like no animal still living today.

Anning made other sensational discoveries over the years: more ichthyosaur skeletons, a flying pterosaur, and hundreds of spiral-shelled ammonites, among others. Of particular scientific significance was her discovery in 1823 of a complete skeleton of the long-necked Plesiosaurus, another top predator of the ancient seas.

Anning’s finds jolted the scientific community into looking for other explanations for the changes they observed in the natural world. But her personal motives were also pragmatic. Fossil collecting was a family business; Anning needed to sell fossils to support her struggling family. In this letter from July 27, 1835, she plies her latest finds to University of Cambridge geologist Adam Sedgwick:

"In answer to your forward of the 24th I beg to say that the price of the Ichthyosaurus 4 feet and half is £50 and the one 3 feet and half is £20 and I think without fear of contradiction I may say that they are the most perfect yet discovered."

Getting the attention of Sedgwick and other prominent male scientists, including Henry De La Beche and William Buckland, was a particularly significant feat for a self-educated, working-class woman of her time. But clues about her life indicate she had the personality for it:

"She glories in being afraid of no one and in saying everything she pleases," noted Anning's friend Anna Maria Pinney in a journal entry from 1831.

It was exactly this chutzpah that inspired author Tracy Chevalier to write Remarkable Creatures, a fictionalized account of Mary Anning's rather difficult life and friendships with other paleontologists:

“I was interested that, though female and working class, Mary managed to work with the middle class male scientists of the day. She was prickly and independent and eccentric. Plus, she was struck by lightning as a baby and survived. Discovering her felt like my own jolt of lightning, and I knew I had to write about her.”

Mary Anning died at age 47 of breast cancer. By then she was a celebrity recognized by the likes of Charles Dickens, and her beloved ichthyosaurs were the recognized rulers of the Jurassic seas.

Those wacky neutrinos are at it again, mystifying physicists by refusing to behave like they're supposed to.

First we had the mystery of the "missing" solar neutrinos, except it turns out they weren't missing, just in disguise -- the three types of neutrinos can change flavors, or "oscillate," into other flavors. They can do this because -- gasp! -- they have a tiny bit of mass, despite the fact that physicists had assumed for decades that neutrinos were massless, like photons.

And now, it seems, neutrinos might be able to violate Albert Einstein's cosmic speed limit by traveling just a wee bit faster than the speed of light, based on a startling new result from the OPERA (Oscillation Project with Emulsion tRacking Apparatus) collaboration. Yeah, you heard me. All the other particles fall in line, heck, even photons obey the speed of light limit, but neutrinos just have to be special. It's like they think the rules don't apply to them.

Honestly, so much has been written about these results in the last few days, it's hard to know where to begin, but here's the gist: In experiments conducted between the European Centre for Nuclear Research (CERN) in Switzerland and a laboratory in Italy, neutrinos were clocked zipping along at 300,006 kilometers per second -- i.e., slightly faster that the speed of light.

Scientists blasted a laser-like beam producing billions upon billions of neutrinos from CERN to the Gran Sasso Laboratory 730 kilometres (453 miles) away. It takes fractions of a second for neutrinos to travel that distance, and when they get to OPERA, they strike the detector, which is comprised of 150,000 bricks of alternating lead plates and photographic emulsion films. To figure out just how fast they're going, you divide the distance between the two points by the measured time it took for the neutrinos to travel between them.

The result: the neutrinos arrived 60 nanoseconds earlier than the 2.3 milliseconds taken by light. "This result comes as a complete surprise," said physicist Antonio Ereditato, spokesman for the OPERA experiment. "We wanted to measure the speed of neutrinos, but we didn't expect to find anything special." Hah! You're studying neutrinos, dude. Expect the unexpected.

As Sean Carroll points out over at Cosmic Variance, this isn't one of those pesky three-sigma results that pop up all the time in particle physics -- most recently in the ongoing search for the Higgs boson -- and then just as quickly disappear as more data is added to the mix, because it turned out to be a statistical fluctuation.

A five-sigma result (five standard deviations) is usually sufficient to claim a discovery. The OPERA collaborators are reporting an impressive six-sigma result -- in other words, it's probably not due to a random statistical fluctuation.

So why aren't they enthusiastically claiming discovery from the highest mountaintop? They recognize that, as the saying goes, extraordinary results demand extraordinary evidence. "Whenever you touch something so fundamental, you have to be much more prudent," Ereditato told The Guardian. "A result is never a discovery until other people confirm it." That's why the team spent six months double, triple, and quadruple checking their analysis. "If there is a problem, it must be a tough, nasty effect, because trivial things we are clever enough to rule out."

Don't Believe the Hype (Yet)

I'm sorry to report that, for all the hoopla, the general consensus that has emerged over the last couple of days is that (a) it's a really interesting, potentially exciting result, but (b) it probably won't hold up over time. Even the OPERA team isn't entirely convinced they're right; they're putting their work out there and basically asking their colleagues to poke holes in it and find anything they've missed. These are world-class physicists, mind you, but nobody is perfect, particularly when it comes to such tricky measurements.

So, what could be the problem? Per Carroll:

There is another looming source of possible error: a “systematic effect,” i.e. some unknown miscalibration somewhere in the experiment or analysis pipeline. (If you are measuring something incorrectly, it doesn’t matter that you measure it very carefully.) In particular, the mismatch between the expected and observed timing amounts to tens of nanoseconds; but any individual “event” takes the form of a pulse that is spread out over thousands of nanoseconds. Extracting the signal is a matter of using statistics over many such events — a tricky business.

A similar method was used by scientists with the MINOS collaboration, which also saw hints of neutrinos traveling slightly faster than light in 2007, although with much smaller statistical significance -- so much so, that Fermilab physicist Joseph Lykken described the result as "inconclusive."

"It's a pretty messy way to try to test a fundamental property," Lykken told Discovery News. "You have a proton beam at CERN that makes the neutrinos, but you don't know which proton made which neutrino. This makes it tough to claim nanosecond timing of the neutrinos. OPERA says they can do this on a statistical basis. Maybe so, but normally in experiments you use something well understood to measure something messy, not the other way around."

Another objection: "In a way, this experiment has been done," according to Marc Sher, a particle physicist with William & Mary College. We can look to the neutrinos detected from Supernova 1987A, which arrived roughly three hours before the light from the exploding star reached the detectors. But that's not because neutrinos traveled faster than light. Rather, they were able to pass right through all the material forming an envelope around the dying star, whereas photons would have to work their way through.

Physicists did the calculations and expected a three-hour delay, and that's exactly what they observed with the neutrinos from SN1987A. However, as Sher (and many others) have pointed out, if the OPERA result is real, those neutrinos should have traveled much faster, so much so that they would have arrived even sooner -- say, in 1984. I think physicists probably would have noticed.

"Supernova neutrinos are known, experimentally, to travel at the same speed as light to better than a part in a trillion," Sher emphasized. "The OPERA claim is that they are traveling faster than light by a part in 30,000." And, well, that's problematic.

John Beacom of Ohio State University told Discovery News that the comparison to SN1987A neutrinos might not be the best one to make: "It's meaningless without knowing how the speed might vary with neutrino energy, distance, etc." If you want a possible good cross-check of the OPERA results, he suggests a closer analog would be to look to experiments like IceCube, which searches for high-energy neutrinos associated with gamma ray bursts.

Sep 23, 2011

Just like the "Heart of the Ocean," the iconic blue-diamond necklace worn by Kate Winslet in James Cameron’s 1997 epic movie, a now untraceable jewel from the Titanic is telling an intriguing story of love and loss.

A gold-plated necklace that belonged to first-class passenger Eleanor Elkins Widener of Philadelphia was stolen last Saturday from the show "Titanic - The Exhibition" at Copenhagen's Tivoli Gardens amusement park.

Known as Nellie to her friends, Eleanor was travelling with her husband George Dunton Widener (the son of the streetcar magnate Peter A.B. Widener), their 27-year-old-son Harry Elkins Widener, and two domestics – maid Amalie Gieger and manservant Edwin Keeping.

The Wideners had left Lynnewood Hall, the 110-room Georgian-style family mansion in Elkins Park, Pennsylvania, on March 13, 1912, for a brief journey to Europe.

"I'm about to make a quick trip to England…I'm really hoping to get a number of books," Harry Elkins Widener, an avid book collector, wrote to a friend.

"We sail on Wednesday at 1 a.m. on the Mauretania and return on April 10th on the maiden voyage of the Titanic," Harry wrote on March 10th.

Indeed the family boarded the "unsinkable" Titanic at Cherbourg, France, on 10th April 1912.

On April 14th, the Wideners, one of the wealthiest families on board, organized a private dinner party in honor of Captain Edward J. Smith. Several distinguished guests, such as Archibald Butt, an advisor to President William Taft, attended.

A little before 9pm, Captain Smith was summoned and politely left for the bridge. Around 11:40 p.m. that night, the Titanic struck an iceberg.

In an article dated 19 April 1912, the Washington Times reported the dramatic last minutes of the Wideners.

"Mrs. Widener did not want to go, and asked to be allowed to stand by her husband. However, Mr. Widener told her to save herself …. Mrs. Widener kissed her husband good-by," the Washington Times quoted a friend survivor.

To persuade his wife to board the lifeboat, George Dunton Widener "told her not to worry, as it was possible that all would be saved, and the danger did not seem great," the survivor recalled.

Harry helped his mother into lifeboat 4 and stood back with his father to await his fate.

The boat rowed away with Eleanor, her maid and 34 other people (all women and children).

George and Harry's bodies, if recovered, were not identified.

Three years after the Titanic tragedy, which sank on 15 April 1912 claiming 1,517 lives, Eleanor Widener built the Harry Elkins Widener Memorial Library at Harvard University.

The library, which originally housed her son’s collection of about 3,300 precious volumes, is now home to 3 million volumes. It features one of the few remaining perfect copies of the Gutenberg Bible, donated by Harry’s brother and sister in 1944.

At the grand opening of the library on Commencement Day, June 24, 1915, Eleanor met Dr. Alexander Rice, a physician and explorer who received an honorary degree that day.

Within a few months, they were married.

According to newspaper reports, the bride, "noted for her beauty," wore a string of pearls which she saved from the Titanic disaster.

"She is said to possess one of the finest collections of jewels in the world. One string of pearls which Mr. Widener gave her for Christmas in 1909 was said to have cost $750,000," the New York Times reported.

Many people believe in ghosts and heaven, and about three in 100 Americans report actually having near-death experiences (NDEs). These typically include an awareness of being dead, out-of-body experiences, meeting dead people, entering tunnels of light, and so on.

But these are stories and anecdotes; what does science have to say?

A new article published in Trends in Cognitive Sciences by neuroscientist Dean Mobbs of the University of Cambridge's Medical Research Council Cognition and Brain Sciences Unit and Caroline Watt at the University of Edinburgh find that "Contrary to popular belief, research suggests that there is nothing paranormal about these experiences. Instead, near-death experiences are the manifestation of normal brain function gone awry, during a traumatic, and sometimes harmless, event."

Mobbs and Watt noted that many classic NDE symptoms are actually reported by people who were never in danger of dying in the first place. This suggests that the perception that one is near death is traumatic and disturbing enough to cause some of the experiences.

Researcher Susan Blackmore, author of Dying to Live: Near-Death Experiences (Prometheus Books, 1993), notes that many NDEs (such as euphoria and the feeling of moving toward a tunnel of white light) are common symptoms of oxygen deprivation in the brain.

The new paper also discussed something called "walking corpse" syndrome, named after French neurologist Jules Cotard. Co-author Watt told Discovery News, "The sufferer feels that he or she is dead, even though not actually near death. It can be associated with trauma and some illnesses. It's not fully understood why individuals suffer from Cotard syndrome, but one possibility is that it's the brain's attempt to make sense of the strange experiences that the patient is having.

This is relevant to NDEs because the near-death experience may also arise out of an attempt to interpret unusual physiological and psychological experiences, and the NDE includes the perception that one is not alive in the normal sense of the word."

Watt's research also busts another myth: that people have "returned from the dead" -- if by dead you mean clinical brain death.

That fact is that no one has survived true clinical death (which is why the experiences are called near-death). Many people have been revived after their heart stopped for short periods of time -- around 20 minutes or more -- but anyone revived from brain death would be permanently and irreparably brain damaged and certainly unable to report their experiences.

"The idea of surviving clinical brain death is mythical," Watt said. "NDEs are sometimes reported after a person experiences some of the preliminary 'stages' of death -- for instance, when the heart stops beating for a while and the person is then revived. I think it's curious, however, that a survey has shown that 82 percent of individuals who have survived being actually near death do not report a near-death experience. That would seem to undermine the idea that these experiences give a glimpse into life after death."

Constantly on the move, performing repetitious behaviors and avoiding eye contact, he puzzled his mother, who didn't know how to handle him at first.

Surely, this isn't normal behavior for a 1-year-old bonobo, who should be learning the ins and outs of his ape social group.

Speculating the roots of Teco's change, his caregivers at Great Ape Trust put forth a surprising theory: What if Teco is autistic?

Such a finding may come as a surprise to the primatology community, which is familiar with the stunning intelligence of Teco's dad, Kanzi. From observing so far, experts think Teco's autistic-like behaviors add to a growing list of similarities between humans and their recent primate ancestors. If the young bonobo has indeed developed a neurological condition akin to autism, then researchers might learn more about the disorder's roots and how it affects other species.

But the claim raises a larger question: Are mental health disorders unique to humans, or are we too ill-equipped to understand the complexity of the nonhuman animal psyche?

It's tough to say, since we can't extrapolate human behavior onto another species. What's worth noting, however, is primate-behavior experts' ability to discern Teco's actions and label them abnormal for his species.

After looking at a previous video demonstrating Teco's strong connection with a human caregiver, I was surprised to learn about changes in this youngster. In the first video, Teco didn't appear to have problems with social issues, such as maintaining eye contact. Yet, between September 2010 and now, something in Teco's development seems to have veered off course.

Could the primate's unnatural rearing or early interaction with humans be affecting his developmental trajectory? It's not clear and likely won't be for some time.

Autism spectrum disorders, limited to humans so far, affect nearly one in every 110 children, according to the Centers for Disease Control and Prevention. Because of the complexity of the condition, it's difficult to know for sure if Teco's behaviors were shaped by the same factors as children who live with signs of autism.

Physicists reported Thursday that sub-atomic particles called neutrinos can travel faster than light, a finding that -- if verified -- would be inconsistent with Einstein's theory of relativity.

In experiments conducted between the European Centre for Nuclear Research (CERN) in Switzerland and a laboratory in Italy, the tiny particles were clocked at 300,006 kilometres per second, slightly faster that the speed of light, the researchers said.

"This result comes as a complete surprise," said physicist Antonio Ereditato, spokesman for the experiment, known as OPERA. "We wanted to measure the speed of neutrinos, but we didn't expect to find anything special."

Scientists spent nearly six months "checking, testing, controlling and rechecking everything" before making an announcement, he said.

Researchers involved in the experiments were cautious in describing its implications, and called on physicists around the world to scrutinize their data, to be made available online overnight.

But the findings, they said, could potentially reshape our understanding of the physical world.

"If this measurement is confirmed, it might change our view of physics," said CERN research director Sergio Bertolucci, a view echoed by several independent physicist contacted by AFP.

In the experiments, scientists blasted a laser-like beam producing billions upon billions of neutrinos from CERN, which straddles the French-Swiss border Geneva, to the Gran Sasso Laboratory 730 kilometres (453 miles) away in Italy.

Sep 22, 2011

“How do we know which numbers to trust and which health studies are
sound? Healthland faces this dilemma every day, so we spoke with Charles
Seife, the rare journalist with an undergraduate degree in mathematics,
from Princeton no less. In his book Proofiness: The Dark Arts of
Mathematical Deception, Seife explores the common ways math can be used
to mislead people.

What is “proofiness”?
It’s the art of using math to tell untruths, the art of using bogus numbers or numbers that are semi-right to mislead.
One example I like is when Quaker Oats had a huge ad campaign to try to
convince people that eating oatmeal could lower cholesterol
dramatically. It put a graph on the back [of the package] that showed a
dramatic decline in cholesterol levels. And there was a drop, according
to a study. But if you look carefully, the Y-axis was manipulated so
that a really very tiny drop looked huge, when in fact, there was only a
few points [decline] out of 200.

And what is the phenomenon you call “randumbness”?
We humans have a hard time recognizing that things can actually have no
[discernible] cause. They are random. The roll of the dice isn’t
influenced by external factors [like wearing your lucky shoes]. That’s
how Las Vegas makes all its money. People think that if they’re winning,
they should keep doing [what they're doing]; if they’re losing they’re
due to win soon. The universe doesn’t care whether you win or lose —
things are just random.

So, it’s the fallacy that comes when we think something is [causally
connected to something else], when in fact there’s no cause behind it. I
like to link it to what I call cause-uistry — what happens when, say,
there is a cancer cluster or you spot a group of people who have more
than the expected number of a certain type of cancer. It may be that
there’s a toxin or something causing it. But by the sheer fact that you
are looking at the entire country, of course there are going to be some
places where there is a more-than-average incidence of cancer. Just
through random chance, in some places there will be an increase in
cancer, and in some places it will be lower than expected.

So cause-uistry is a glib name for the fallacy that correlation
equals causation. Just because two things seem to be related doesn’t
mean that one affects the other. [Still] our brains lead us to connect
things even if they are not connected. One fun example: when I was doing
reporting on something else, a member of Congress tried to pitch me on
building more power plants. He said that if you increase power
production, then infant mortality drops. It’s true. It’s also true that
when Internet use goes up, infant mortality drops. And car driving. Of
course, those are all symptomatic of a high-tech society that has good
health care.”

Sep 21, 2011

“She finished the books and wanted more. Before her mother could
fetch some, Lonni Sue started making grids with words hidden in them.
Thousands of puzzles poured out of her. Wearing thin the pages of a
paperback dictionary, she created elaborate word lists, then puzzles
from the lists and then images from the puzzles. A grid of words for
things that hang in the closet took the shape of a coat hanger. Words
related to trousers formed a pair of pants. Her vocabulary seemed to
open a new door for her creativity.

Enter Barbara Landau. She had gone to high school with Lonni Sue in
the Princeton, N.J., area. (“She was brilliant,” Landau remembers.)
Today, Landau is an expert on cognitive science at Johns Hopkins
University. She had followed Lonni Sue’s career as an artist for years
and now, with Hopkins colleague Michael McCloskey, she explored Lonni
Sue’s amnesia intensively. It was Landau who brought Lonni Sue’s art to
the Walters.

Scientists often work with people who have lost the use of part of the brain to learn how the normal brain works.

After working with Lonni Sue, Landau concludes: “If we think that art
and creativity have to be rooted in what we know about ourselves or
what we remember about ourselves, that clearly is not the case.”

Lonni Sue has been full of surprises. She can remember how to fly an
airplane — “It’s like dancing in the sky,” she said in an interview —
but she can’t remember the death of her father.

She can’t recognize art she treasured before her illness — “Starry
Night” by Vincent van Gogh, for example. Yet she can instantly recognize
her own past work.

She can’t remember that she was married for 10 years, but she can
remember how to play Bach suites on her viola. But if, as she’s putting
her instrument away, her mother thanks her for playing, she’s likely to
look astonished and say, “Oh, did I play?”

She cannot produce the kind of finished art she once drew, but her
work shows flashes of her old skill as well as her characteristic whimsy
and puns.

Feisty, raptor dinosaurs didn't just use their sharp claws for show -- a new fossil suggests they may have brandished their butcher's hook-like talons as weapons.

A newly found feathered dinosaur, named Talos sampsoni, is related to the iconic velociraptor of Jurassic Park fame.

The fossil shows the dinosaur's foot was damaged, and researchers think they know why.

"This raptor dinosaur specimen is special because it shows evidence of having broken the toe on the foot that bears an enlarged talon, an injury we are interpreting as sustained during combat with other members of the species or in hunting prey," Lindsay Zanno, lead author of a study published in PLoS ONE, told Discovery News.

Zanno is an assistant professor of anatomy at the University of Wisconsin, Parkside, and a research associate at Chicago's Field Museum of Natural History.

The purpose of this recurved claw has been a mystery. At least one function is now evident: The dinosaurs likely used the talon to kick the you-know-what out of others.

The new dinosaur was named in honor of paleontologist Scott Sampson and the mythical Greek figure Talos, a bronze giant who had wings and threw stones. It's unclear if this scrappy new dinosaur threw stones as well, but the researchers do know that it was feathered and bird-like.

The dinosaur represents the first definitive troodontid theropod ("beast-footed") to be named from the Late Cretaceous of North America in more than 75 years.

Western North America at that time was part of the "lost continent" of Laramidia. It was home to numerous dinosaurs, particularly during the Late Cretaceous, 99.6 to 66.5 million years ago.

Troodontids like T. sampsoni probably were omnivores, eating whatever they could find in sight. Specimens from other species suggest these theropods laid beautifully colored eggs and slept with their heads tucked underneath their "wings," as birds still do today.

Colorful angelfish -- beauties of coral reef habitats -- have capitalized on a remarkable set of jaws to exploit niches inaccessible to other reef denizens, according to new research.

Fish that eat food floating free in the water column capture their prey either through suction feeding -- sucking water, and their prey along with it, in through their gaping mouths -- or through "ram" feeding, where they open their mouths wide and surge forward, capturing food in their paths.

But angelfish are able to scrape, clip, and rip food that's tethered to undersea surfaces using a "grab and tear" mechanism that relies on a specialized jaw design.

"They can protrude their upper and lower jaw out away from their head and then bite really hard," said Peter Wainwright of the University of California, Davis, who was not a part of the study. "Imagine if you could just sit there at the table and extend your jaw out toward the plate. A big angelfish can extend its jaws a couple of inches. They can reach into nooks and crannies on the reef. They're powerful biters. They can yank."

In addition to a protrudable jaw, they have an extra joint in their lower jaw that allows them to bite while their jaws are extended. And they have an extra set of bristle-like teeth that gives them a firm grasp of their food.

"They're basically able to do something that other reef fish can't," thanks to their unusual jaw, by attacking food that's firmly attached to a reef surface, and pulling it out of crevices that other fish can't reach, said Nicolai Konow now of Brown University in Providence, RI, who led the new study.

While in some species, such specialized structures allow the animal to monopolize a single food type, angelfish have used this evolutionary breakthrough to expand into many niches on the reef.

"These guys are sort of jacks of all trades," Konow said.

Different angelfish species have retained the same jaw structure, but have specialized, instead, by varying their size and their gut to access many types of food.

With a range of patterns and colors including blue, yellow, black and white, the 80 or so different species of angelfish span more than a tenfold size difference and consume everything from sponges, algae, anemones and plankton, Konow and colleague David Bellwood of Australia's James Cook University reported.

By evolving into a range of sizes and gut configurations, the fish could adapt to different habitats, while still using their unique jaw. (One group has adapted to feed on unattached food in the water column and that group has changed its jaw structure the most.)

As Darwin described, species of finches in the Galapagos Islands evolved different beak sizes and shapes to capitalize on different food sources, and the angelfish findings are similar, but with a twist.

"It would be as though you went to the Galapagos and found some finches are eating seeds and some are eating insects, but darn, they all look the same, except one is the size of a crow and the other is the size of a small sparrow," Wainwright said.

"This is an interesting pattern that you can get different specialists in different things using a system that's not getting heavily modified," Wainwright said. "That is pretty interesting. You don't see that very often."

The relationship between a galaxy and its black hole is as mystifying as any of those found among families on Earth.

Scientists don't even know which came first -- galaxies or their black holes, those regions of space so dense with matter that even photons of light fall prey to their gravitational jaws.

Scrambling the cosmic conundrum anew is a discovery of small dwarf galaxies with giant black holes, a finding that upends currently held theories of galaxy formation.

Previous studies showed that as a galaxy grows and evolves, its black hole seems to grow and evolve too, at least for the big clusters.

Using data from the Hubble Space Telescope, astronomers now find that some small galaxies in the distant universe have disproportionately sized black holes.

"They seem to be out of sync in some fundamental way," astronomer Sandra Faber, with California's Lick Observatory, told Discovery News. "These black holes are too massive given their star content at that time," Faber said. "They've grown up too fast. The holes have gotten ahead of the teen-age galaxies."

Even more puzzling: the telltale bulge of stars associated with super-massive black holes in large galaxies is noticeably absent in these smaller siblings, suggesting there may be more than one way to grow a black hole.

The finding is based on studies of 28 dwarf galaxies huddled together some 10 billion light years from Earth. While black holes, by definition, cannot be seen, astronomers look at the radiation streaming from stars surrounding the black hole to figure out its size and features.

"People might have thought that only once a galaxy gets to its old age and grows this bulge could you grow a super-massive black hole," lead researcher Jonathan Trump, with the University of California at Santa Cruz, told Discovery News.

Sep 20, 2011

It must be ISS flyover video season, because here's another breathtaking beauty made from images taken by the Expedition 28 crew aboard the space station! Here we get to witness the glamor of the Aurora Australis -- a.k.a. the Southern Lights -- as the International Space Station orbits high above.

The Aurora Australis is the southern hemisphere's version of the Aurora Borealis, and is created in the same way: high-energy ions emitted from the sun collide with Earth's magnetic field and excite atoms of various elements located in the upper atmosphere, which then release light energy we can see.

The colors of the aurora are determined by the type of atoms releasing light as well as their altitudes. The most common gas at lower levels of the Earth's ionosphere is oxygen, which emits light in the green and yellow end of the spectrum -- colors our eyes detect particularly well.

Other colors, like reds, blues and purples, are also possible but harder to detect without using longer-exposure photography.

Besides shimmering sheets of aurorae, a high-altitude phenomenon called airglow is also visible as a thin line of pale yellow light surrounding Earth's limb. This is caused by energy released by molecules high in the atmosphere that were charged up during the day by ultraviolet light from the sun... not unlike a glow-in-the-dark sticker!

Between this video and the previous one posted here, it's no wonder that the astronauts lucky enough to work on the Space Station love their jobs as much as they do. In spite of all the inherent risks to working in low-Earth orbit, you simply can't beat the view.

A five-inch-long baby dinosaur with a short nose, armor and spikes went belly-up and likely drowned in what is now the Washington, D.C. beltway, say scientists, who describe the find as a new species as well as the first hatchling of any dinosaur species ever recovered in the eastern United States.

The tiny dinosaur, Propanoplosaurus marylandicus, is the youngest nodosaur ever found. This group of short-necked, plant-eating dinosaurs reached about 30 feet long when fully grown and had powerful jaws and small teeth.

"Dinosaurs grew up faster than we ever imagined," said Ray Stanford, a Maryland-based dinosaur tracker who was the lead author of a study on the find in the Journal of Paleontology. "We can tell that this little guy was just a hatchling because the bones were elastic and cartilaginous upon death and not ossified."

Stanford found the new 110-million-year-old nodosaur while searching a creek bed in Maryland's Prince George's County after an extensive flood. The area, according to Stanford, was quite a hotbed of dinosaur activity during the Early Cretaceous.

Major predators, such as huge meat-eating Acrocanthosaurus, lived in the region, along with numerous large sauropods, and other plant-eaters like Hypsilophodon and Iguanodon.

"The climate was quite warm and tropical," he said, adding that it was full of lush palm-like trees, such as Cycadophytes members.

The living wasn't always easy for dinosaurs, however, as the little nodosaur proves. Stanford and his team believe the baby dinosaur, which grew to only five inches long, drowned before getting buried by sediment in the stream. They base this on the location and the fact that the dinosaur was preserved on its back. Stanford said dinosaurs that drown exhibit "float and bloat" characteristics shared by this specimen.

Weishampel, a paleontologist and a professor of anatomy at the Johns Hopkins School of Medicine, led a computer analysis of the baby dinosaur's skull, comparing its bumps, grooves and proportions to 10 other species of ankylosaurs, the group that contains nodosaurs.

They determined the dinosaur was closely related to other nodosaurs, but had distinctive features, such as a particularly short snout, which earned its designation as a new species.

"We didn't know much about hatchling nodosaurs at all prior to this discovery," Weishampel was quoted as saying in a press release. "And this is certainly enough to motivate more searches for dinosaurs in Maryland, along with more analysis of Maryland dinosaurs."

Stanford indicated the short-snouted dinosaur, preserved as a natural cast, softens the image of its tougher looking armored parents.

"Babies tend to be cute with their short noses, so this one fits that description," he said. "It also had legs that were disproportionately long for its body, allowing for running."

Exactly 20 years ago, on Sept. 19, 1991, German hikers Erika and Helmut Simon spotted something brown while walking near a melting glacier in the Ötztal Alps in South Tyrol.

As they got closer, they realized with horror that it wasn't just some sort of rubbish: a human corpse was lying with the chest against a flat rock.

Only the back of the head, the bare shoulders and part of the back emerged from the ice and meltwater.

The hikers thought the body belonged to an unfortunate victim of a mountaineering accident a few years back. In fact, they discovered one of the world's oldest and best preserved mummies.

To commemorate the 20th anniversary of this sensational discovery, here are 20 known and lesser known facts about the Neothiltic frozen mummy.

1. An incredible chain of coincidences allowed the Iceman to remain intact: he was covered by snow shortly after his death and later by ice; the deep gully where the Iceman lay prevented the body from being ground up by the base of the glacier; the body was exposed to damaging sunlight and wind only for a short time in 1991 between the time the mummy thawed and the accidental discovery.

2. It was an Austrian reporter, Karl Wendl, who first named the mummy "Ötzi," referring to the Ötzal Alps where it was found. According to a resolution by the South Tyrol Provincial Government, the official name for the mummy is "Der Mann aus dem Eis" -- "L'Uomo venuto dal ghiaccio" (The man who came from ice).

3. Soon after the mummy was recovered, a harsh controversy arose on which soil -- Italian or Austrian -- it was found. A survey of the border carried out on Oct. 2, 1991 established that the mummy lay 303.67 feet from the border in South Tyrol, in Italy.

4. Radio carbon dating established that the Ötzi lived around 5,000 years ago, between 3350 and 3100 B.C.

5. Recent investigations established that he had brown eyes, not blue as previously thought.

8. The Iceman had a remarkable diastema, or natural gap, between his two upper incisors. He also lacked wisdom teeth. Even though he suffered from cavities, worn teeth and periodontal diseases, he still had all his teeth when he died at around 45.

9. Ötzi could have been a little better endowed. The man's natural mummification and dehydration in the Alpine glacier produced a "collapse of the genitalia," which left the Iceman with an almost invisible member.

10. The Iceman's last meal probably consisted of a porridge of einkorn, meat and vegetables. Researchers are still investigating the sampled material to determine the exact nature on the Iceman’s last meal.

11. Three gallbladder stones were recently found which, in combination with the previously identified atherosclerosis, show that Ötzi’s diet may have been richer in animal products than previously thought.

12. The Iceman's stomach also contained 30 different types of pollen, which ended up there with the food he ate, the water he drank and the air he breathed. The pollen showed that he died in the spring or early summer.

13. Analysis of the isotopic composition of Ötzi's tooth enamel and bones suggest that the man was born and lived in what is now South Tyrol. He probably spent his childhood in the upper Eisack Valley or the lower Puster Valley. He lived at least ten years in the Vinschgau prior to his death.

14. Among the clothing and items found with the mummy, one of the most important pieces is the copper-bladed axe. Archaeological experiments showed that the axe could fell a yew tree in 35 minutes without sharpening.

15. Ötzi's body is covered with over 50 tattoos made with fine incisions into which charcoal was rubbed. In the shape of lines and crosses, they were probably used as pain-relieving treatments. Indeed, the tattooed areas correspond to skin acupuncture lines, which predate acupunture in Asia by two thousand years.

16. Many theories have been proposed on Ötzi' social status. Among the various theories, the Iceman was identified with a shaman, a mineral prospector looking for ore deposits in the mountains, a hunter, a trader, a shepherd, and a man banished from his community.

17. The Iceman had been involved in a fight shortly before his death. He was shot with an arrow which pierced the subclavian artery and also suffered a blow to the death just before dying.

18. Ötzi's belonged to the European genetic haplogroup K. He was probably infertile.

Around 65 million years ago, an asteroid plummeted to Earth, triggering a cascade of events that led to the demise of the dinosaurs, among other life forms.

The guilty party, previous studies showed, hailed from a family of asteroids called the Baptistina, residents of the main asteroid belt between Mars and Jupiter. One of their members, the story goes, crashed into a sizeable neighbor some 160 million years ago, and shattered, sending at least one hefty chunk hurling toward Earth.

New data refined the age estimates of the suspect's family, casting doubt they were around at the right time to cause the impact. Rather, the original parent Baptistina asteroid seems to have broken apart closer to 80 million years ago, about half as long as originally proposed, which doesn't give any large pieces enough time to have reached Earth to trigger the dinosaur-killing impact, says astronomer Amy Mainzer, with NASA's Jet Propulsion Laboratory in Pasadena, Calif.

The WISE team reached its conclusion after surveying more than 157,000 asteroids, including 1,056 members of the Baptistina family.

According to her website, Sally Morgan is "Britain's best-loved psychic". She is certainly a very successful psychic – she has just released her third book and is currently filming the third series of Psychic Sally on the Road for Sky LIVING. But an incident that took place a few days ago may cause a few of her fans to wonder whether Morgan is deserving of their adoration. Could it be that, like so many self-professed psychic superstars in the past, Morgan is nothing more than a self-serving con artist?

Let me describe what happened so that you can make up your own mind. On Monday 12 September, a caller named Sue phoned the Liveline show on RTÉ Radio 1, an Irish radio station. Sue said that she had attended Morgan's show the previous night at the Grand Canal Theatre in Dublin and had been impressed by the accuracy of the readings she made in the first half of the show.

But then something odd happened. Sue was sitting in the back row on the fourth level of the theatre and there was a small room behind her ("like a projection room") with a window open. Sue and her companions became aware of a man's voice and "everything that the man was saying, the psychic was saying it 10 seconds later."

Sue believes, not unreasonably, that the man was feeding information to Sally through an earpiece attached to her microphone. For example, the voice would say something like "David, pain in the back, passed quickly" and a few seconds later Sally would claim to have the spirit of a "David" on stage who – you'll never guess – suffered from back pain and passed quickly.

A member of staff realised that several people near the back of the theatre were aware of the mystery voice and the window was gently closed. The voice was not heard again.

Sue speculated, again not unreasonably given the history of psychic frauds, that the man was feeding Sally information that had been gathered by engaging members of the audience in conversation in the foyer before the show began. This is a technique widely used by psychic fraudsters, as audience members will naturally discuss with each other who they are hoping to hear from "on the other side", how their loved one died, and so on.

Subsequent callers to the radio programme supported Sue's account.

The theatre's general manager, Stephen Faloon, claimed that the voice heard by the audience was actually the voices of two members of staff working for the theatre, not someone supplying information to Sally. Sally Morgan Enterprises also denied that the medium was being fed information during the show.

This episode is reminiscent of the exposure of faith healer Peter Popoff by James Randi in 1986. Popoff would wow his audiences by giving specific and accurate details of their medical problems before claiming to cure them with his divine powers. This information was, according to Popoff, provided to him directly by God. It was certainly an effective technique, as at this time Popoff was raking in around $4m per month (tax-free) from his poor, sick and uneducated followers.

Randi, with the assistance of investigator Alexander Jason, convincingly demonstrated that Popoff was actually receiving the "divine" information from his wife via a hearing aid. Following his exposure on The Tonight Show Starring Johnny Carson, Popoff declared bankruptcy in 1987.

In a more rational world, that would have been the end of Popoff's career as a faith healer. Sadly, we do not live in a rational world. Popoff is back, earning more than ever by fleecing his flock using exactly the same techniques that Randi exposed, plus a few new ones, such as the sale of "Miracle Spring Water". According to ABC News, Popoff's ministry received more than $9.6m in 2003 and more than $23m in 2005. In that year, Popoff paid himself and his wife a combined total of almost a million dollars (not to mention two of his children receiving more than $180,000 each).

Since the heyday of mediumship during the Victorian era, exposure as frauds has typically done little to diminish the popularity of alleged psychics in the eyes of their followers.

It is important to realise that many self-professed psychics, possibly the majority, are sincere in their beliefs that they possess a "gift". Such practitioners are probably unintentionally using some of the same techniques used by so-called cold readers to convince themselves and their sitters that they are tapping into some paranormal source of information. Because the cold reading technique is not being exploited deliberately and systematically, such readings are usually unimpressive to anyone except hardcore believers.

But con artists can use cold reading to convince complete strangers that they know all about them. It relies on the clever use of language, careful observation, intelligent guesswork, and the production of vague and ambiguous statements that the sitter interprets (and remembers) as being more specific than they actually were. In a skilled practitioner, cold reading can produce much more impressive results than the rather amateurish readings produced by most psychics.

Sep 19, 2011

For the first time, USC scientists have mapped out a neuroreceptor. This scientific breakthrough promises to revolutionize the engineering of drugs used to treat ailments such as Alzheimer's disease and schizophrenia.

The team produced the world's first high-resolution images of the α7 (Alpha 7) receptor, a molecule responsible for transmitting signals between neurons -- particularly in regions of the brain believed to be associated with learning and memory.

Using the image, scientists will be better equipped to design pharmaceuticals specifically to interact with the receptor, instead of blindly using a trial-and-error approach.

"A lot of interest in this work will come from pharmaceutical companies," said corresponding author Lin Chen, professor of biological sciences and chemistry at the USC Dornsife College of Letters, Arts and Sciences. "They really have no clear picture of this. They don't know how or why [their drugs] work."

The high-resolution image will also help neuroscience researchers study how these receptors receive and transmit neuronal signals, a question that has puzzled researchers for decades.

The article, co-authored with scientists from the Keck School of Medicine of USC and the Mayo Clinic College of Medicine, appears in Nature Neuroscience this month.

The findings follow up on Chen's earlier landmark achievement, deciphering the inner workings of a nicotine receptor in 2007.

Developing an image of the α7 receptor was no simple task, which is partly why it has taken until now to achieve this despite the wide interest in the understanding the receptor's structure. Attempts to decipher neuroreceptors have been ongoing for 30 years.

"This has been a longstanding challenge," Chen said. The challenge is twofold, he said. It is difficult to obtain enough receptor protein for structural analysis, and the flexible nature of these receptors makes them difficult to crystallize -- a necessary step for high-resolution imaging.

"You can't study it directly in its natural form, so you have to engineer it," Chen said.

In the case of α7, Chen's collaborator, Dr. Steve Sine from Mayo Clinic, engineered a chimera, a Frankenstein molecule sharing about 70 percent of its structure in common with the α7 that reacted to stimuli in the same way that natural α7 does.

The next step was to form crystals with these proteins for high-resolution study. This turns out to be particularly difficult for neuronal receptors because they are intrinsically flexible -- they need to bind to a neurotransmitter, a small molecule that acts as a messenger in the nervous system, and transmit the signal across the protein body. Moreover, these receptors are decorated with sugar molecules that add further flexibility to the system.

Now watch it 14 more times for an idea of what the astronauts aboard the International Space Station (ISS) get to see every day. No wonder after five months up there they still don't want to come down!

This gorgeous video was made by science teacher James Drake using images downloaded from The Gateway to Astronaut Photography of Earth. This is a great online resource with basically all of the images taken from orbit, categorized into a searchable database by region and date. He used a free program called VirtualDub to create the final edit.

ames explains on YouTube: "This movie begins over the Pacific Ocean and continues over North and South America before entering daylight near Antarctica. Visible cities, countries and landmarks include (in order) Vancouver Island, Victoria, Vancouver, Seattle, Portland, San Francisco, Los Angeles. Phoenix. Multiple cities in Texas, New Mexico and Mexico. Mexico City, the Gulf of Mexico, the Yucatan Peninsula, Lightning in the Pacific Ocean, Guatemala, Panama, Columbia, Ecuador, Peru, Chile, and the Amazon. Also visible is the earths ionosphere (thin yellow line) and the stars of our galaxy."

The naturalist joined three Nobel laureates, the atheist Richard Dawkins and other leading scientists in calling on the government to tackle the "threat" of creationism.

Gordon Brown's government issued guidance to all schools that the subject should not be taught to pupils, but neither they nor the coalition government enshrined the recommendation in law.

In a statement on a new campaign website, the 30 scientists and campaign groups including the British Science Association demanded creationism and "intelligent design" be banned outright.

Prof Colin Blakemore, the neurobiologist, Sir Paul Nurse, the President of the Royal Society, and former Royal Society director of education Rev Prof Michael Reiss were among the signatories.

Rev Prof Reiss, who has described evolution as "God's work", resigned from his Royal Society post in 2008 after suggesting science lessons ought to include discussion of creationism.

Speaking ahead of the launch today he said: "Evolution is an extremely powerful idea that lies at the heart of biology.

"At the same time, it's a sufficiently simple concept that there's no good reason why it should be left out of the primary curriculum. If creationism is discussed, it should be made clear to pupils that it is not accepted by the scientific community."

Last year the campaign group, led by the British Humanist Association (BHA) and comprising many of the same members, called for evolution to be taught in all primary schools.

Prof Dawkins said: "We need to stop calling evolution a theory. In the ordinary language sense of the word it is a fact. It is as solidly demonstrated as any fact in science."

Most schools in England teach evolution, the idea popularised by Charles Darwin that all living things developed from primitive organisms through a process of natural selection.

But the arguments of creationists, who believe God built the world in six days in line with the story of Genesis, and of devout Muslims have become steadily more popular in recent years.

Andrew Copson, chief executive of the BHA, said: "Evolution is probably the most important idea underlying biological science and we support the view of many experts that it should be introduced right from primary level in all state-maintained schools.

Sep 18, 2011

Florida has the world's worst invasive amphibian and reptile problem, and a new 20-year study led by a University of Florida researcher verifies the pet trade as the No. 1 cause of the species' introductions.

From 1863 through 2010, 137 non-native amphibian and reptile species were introduced to Florida, with about 25 percent of those traced to one animal importer. The findings appear online September 15 in Zootaxa.

"Most people in Florida don't realize when they see an animal if it's native or non-native and unfortunately, quite a few of them don't belong here and can cause harm," said lead author Kenneth Krysko, herpetology collection manager at the Florida Museum of Natural History on the UF campus. "No other area in the world has a problem like we do, and today's laws simply cannot be enforced to stop current trends."

Florida law prohibits the release of non-native species without a state permit, but offenders cannot be prosecuted unless they are caught in the act. To date, no one in Florida has been prosecuted for the establishment of a non-indigenous animal. Researchers urge lawmakers to create enforceable policies before more species reproduce and become established. The study names 56 established species: 43 lizards, five snakes, four turtles, three frogs and a caiman, a close relative of the American alligator.

"The invasion of lizards is pretty drastic considering we only have 16 native species," Krysko said. "Lizards can cause just as much damage as a python. They are quicker than snakes, can travel far, and are always moving around looking for the next meal."

Defined by the U.S. Department of Agriculture as organisms "whose introduction causes or is likely to cause economic or environmental harm or harm to human health," invasive species are a growing concern for residents and policymakers. Only three species were intercepted before reaching the wild and researchers documented 137 introductions. The study also shows no established, non-native amphibian or reptile species has been eradicated.

Floridians have experienced some of the damage these animals can cause, from iguanas that destroy cement walls to Burmese pythons released in the Everglades that eat protected species. While the impact of many of the introduced species has not been determined, the study provides new information about how, why and when they entered the state.

The first introduction in 1863 was of the greenhouse frog, native to the West Indies. One of the most easily recognized species is the brown anole, the first introduced lizard, which reached Florida from Cuba via cargo ships in 1887. Until about 1940, nearly all non-native species arrived through this accidental cargo pathway, but the boom in popularity of exotic terrarium animals in the 1970s and 1980s led to the pet trade being accountable for 84 percent of the introductions, Krysko said.

"It's like some mad scientist has thrown these species together from all around the world and said, 'hey let's put them all together and see what happens,' " Krysko said. "It could take decades before we actually know the long-term effects these species will have."

Other pathways include biological control, in which an animal is intentionally released to control a pest species, and accidental introduction through the zoo or plant trade. The study will serve as a baseline for establishing effective policies for control or eradication, said Fred Kraus, a vertebrate biologist at the Bishop Museum in Honolulu who helped establish policies for invasive amphibians and reptiles in Hawaii.

"This paper by Kenney and company I think is a good example of the approach that needs to be taken, providing the detail and being rather cautious in making immediate claims that things are established until there is evidence for it," Kraus said. "There is a lot more work going on now, but for years it was just ignored. For years, climate change was ignored, too. You know, humans just tend to ignore bad news until you can't ignore it anymore."

One of the greatest obstacles pet owners face is how to feed and house an exotic animal that has become too large or difficult to handle, Krysko said.

"The biggest example is the Burmese python," Krysko said. "It's a large constrictor and has definitely shown impact on native species, some you just can't even find anymore."

Language change among our prehistoric ancestors came about via the arrival of immigrant men -- rather than women -- into new settlements, according to new research.

The claim is made by two University of Cambridge academics, Peter Forster and Colin Renfrew, in a report to be published in Science on September 9.

They studied the instances of genetic markers (the male Y chromosome and female mtDNA) from several thousand individuals in communities around the world that seem to show the emergence globally of sex-specific transmission of language.

From Scandinavian Vikings who ferried kidnapped British women to Iceland -- to African, Indian and Polynesian tribes, a pattern has emerged which appears to show that the arrival of men to particular geographic locations -- through either agricultural dispersal or the arrival of military forces -- can have a significant impact on what language is spoken there.

Professor Renfrew said: "It may be that during colonisation episodes by emigrating agriculturalists, men generally outnumber women in the pioneering groups and take wives from the local community.

"When the parents have different linguistic backgrounds, it may often be the language of the father which is dominant within the family group."

Dr Forster, of Murray Edwards College, also pointed to the fact that men have a greater variance in offspring than women -- they are more likely to father children with different mothers than vice versa. This has been recorded both in prehistoric tribes such as the 19th and 20th century Polar Eskimos from Greenland and in historic figures like Genghis Khan, who is believed to have fathered hundreds of children.

Indeed, his Y chromosome is carried by 0.5 per cent of the world's male population today.

Perhaps the most striking example of sex-biased language change however comes from a genetic study on the prehistoric encounter of expanding Polynesians with resident Melanesians in New Guinea and the neighbouring Admiralty Islands. The New Guinean coast contains pockets of Polynesian-speaking areas separated by Melanesian areas. The Polynesian mtDNA level (40-50%) is similar in these areas regardless of language, whereas the Y chromosome correlates strongly with the presence of Polynesian languages.

Past studies have shown similar findings in the Indian subcontinent among the speakers of Tibeto-Burman and among the immigrant Indo-European languages as opposed to indigenous Dravidian languages.

In the Americas, too, language replacement in the course of postulated farming dispersal has also been found to correlate for the Uto-Aztecan language family.